Signal measurement devices, such as vector network analyzers (VNAs) and scalar network analyzers (SNAs), are commonly used for measuring parameters indicative of performance of a device under test (DUT). A technician can measure the performance of an antenna in a cellular network, for example, by disconnecting the antenna from a transmitter associated with the antenna and connecting the antenna to the signal measurement device. The signal measurement device can transmit test signals and receive reflected signals in response. However, signal measurement devices commonly operate at powers below 100 milliwatt (mW) (i.e., below 20 dBm), much lower than typical transmit powers of DUTs.
In a telecommunication network environment, many opportunities present themselves for inadvertently damaging equipment via accidental exposure to a high power signal source. For example, an antenna for a high power transmitter can be remotely connected to the transmitter via multiple cables. For example, a cable leading to an antenna and a cable leading from a high power transmitter may be connected together in a jumper room. A technician testing the antenna will typically do so in the jumper room by disconnecting the appropriate cable and reconnecting the cable to a signal measurement device. This presents an opportunity for a low power signal measurement device to be accidentally connected with a cable leading to a high power transmitter rather than to the antenna. A signal transmitted at the high powers associated with a transmitter for a cellular site can damage the circuitry of a signal measurement device, which is designed to operate at powers many magnitudes lower.